Does the use of recombinant AAV2 in pulmonary gene therapy damage lung function?
ABSTRACT Forty-eight BALB/c mice were divided into two groups of 24 animals each. In the control group (CTRL) saline was intratracheally instilled, while the virus group (VR) received rAAV2-GFP (4 x 10(9) particles). These groups were subdivided into four sub-groups (n=6). Pulmonary mechanical parameters were analyzed after 3 weeks (VR1d3w) and at 1 (VR2d1w), 2 (VR2d2w) and 3 weeks (VR2d3w) after a second AAV2 dose. Fractions of the area of alveolar collapse and the amount of polymorpho- and mononuclear cells were determined by point-counting technique. Viral transduction was evaluated by immunohistochemistry. Lung mechanical data were similar in all groups. However, there was an increase in airway and lung parenchyma cellularity and in the fraction of area of alveolar collapse in the VR2d2w group, which nonetheless decreased with time. There was no evidence of apoptosis in any group. In conclusion, the gene transfer vector AAV2 induces, in the lung, a discrete inflammatory reaction that does not affect either baseline lung mechanics or airway hyperresponsiveness.
- SourceAvailable from: Miquéias Lopes-Pacheco[Show abstract] [Hide abstract]
ABSTRACT: Background/Aims: Vectors derived from adeno-associated viruses (AAVs) are important gene delivery tools for treating pulmonary diseases. Phosphorylation of surface-exposed tyrosine residues from AAV2 capsid targets the viral particles for ubiquitination and proteasome-mediated degradation, and mutations of these tyrosine residues lead to highly efficient vector transduction in vitro and in vivo in different organs. We evaluated the pulmonary transduction efficiency of AAV8 vectors containing point mutations in surface-exposed capsid tyrosine residues. Methods: Male C57BL/6 mice (20-25 g, n=24) were randomly assigned into three groups: control group animals received intratracheal (i.t.) instillation of saline (50 μl), wild-type AAV8 group, and capsid mutant Y733F AAV8 group, which received (i.t.) AAV8 vectors containing the DNA sequence of enhanced green fluorescence protein (eGFP). Four weeks after instillation, lung mechanics and morphometry, vector transduction (immunohistochemistry and mRNA expression of eGFP), and inflammatory cytokines and growth factor expression were analyzed. Results: Tyrosine-mutant AAV8 vectors displayed significantly increased transduction efficiency in the lung compared with their wild-type counterparts. No significant differences were observed in lung mechanics and morphometry between experimental groups. There was no evidence of inflammatory response in any group. Conclusion: AAV8 vectors may be useful for new therapeutic strategies for the treatment of pulmonary diseases. © 2014 S. Karger AG, Basel.08/2014; 34(3):681-690.
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ABSTRACT: Allergic asthma is caused by aberrant helper T (T(H)) type 2 immune responses in susceptible individuals, characterized by airway hyperresponsiveness, chronic airway inflammation, and mucus hypersecretion. Its prevalence continues to increase, but optimal treatment remains a challenge. The transcription factor T-bet is a master regulator of T(H)1 lineage commitment and strongly promotes interferon gamma expression during T(H)1 cell differentiation. The aim of this study was to explore the role of intranasal delivery of T-bet on the differentiation of T(H) cell subsets and airway inflammation in the ovalbumin (OVA)-induced mouse model of allergic airway inflammation. BALB/c mice were sensitized by intraperitoneal injection of OVA and challenged with nebulized OVA. Four days before the inhalation challenge, the sensitized mice were subjected to intranasal delivery of a recombinant adeno-associated virus vector carrying murine T-bet gene (AAV-T-bet). Expression of the transcription factors T-bet, GATA3, and Foxp3 was then assayed in the lungs, and airway histology was analyzed along with other inflammatory parameters, such as eosinophils and cytokines in bronchoalveolar lavage (BAL) fluid, and total and OVA-specific immunoglobulin (Ig) E in serum. Intranasal administration of AAV-T-bet efficiently balanced the T(H)1/T(H)2 transcription factor and cytokine profile and significantly decreased the number of eosinophils in BAL fluid. It also resulted in a reduction of peribronchial inflammation scores and serum IgE levels in OVA-sensitized and challenged mice during the effector phase. Our data show that intranasal delivery of T-bet can promote a T(H)1 immune response, restore a balanced Th immune response, and inhibit airway inflammation during the challenge phase in a mouse model of allergic airway inflammation.Journal of investigational allergology & clinical immunology: official organ of the International Association of Asthmology (INTERASMA) and Sociedad Latinoamericana de Alergia e Inmunología 02/2008; 18(5):357-65. · 1.89 Impact Factor
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ABSTRACT: This study investigated whether repeated administration of recombinant adeno-associated virus type 5 (rAAV5) to the airways induces inflammatory processes in the lungs of BALB/c-mice, with mechanical and histologic changes. Saline was instilled intratracheally in the control group, and rAAV5-green fluorescence protein (GFP) (4x10(11)particles) in the virus group (VR). These groups were subdivided into four subgroups: one dose analyzed 3 weeks later (VR1d3w) and two doses analyzed 1 (VR2d1w), 2 (VR2d2w) and 3 weeks (VR2d3w) after the second dose. Lung morphometry, mechanical parameters, airway responsiveness, rAAV5-GFP transduction and the expression of inflammatory cytokines were investigated. No significant differences in lung mechanics, airway responsiveness, and morphometry were observed. Re-administration of rAAV5 vector resulted in a decrease in GFP mRNA expression in the VR2d3w group. There was no evidence of inflammatory response or apoptosis in any group. rAAV5 did not induce an inflammatory process, mechanical or morphometric changes in the lungs. AAV5 may be an appropriate vector for lung gene therapy.Respiratory Physiology & Neurobiology 07/2009; 168(3):203-9. · 2.05 Impact Factor